New turbines for Exelon plants

US utility Exelon is upgrading steam turbines at six of its nuclear power units. The $420 million project should result in about 240 MWe more power.

Exelon's Quad Cities, Dresden and Peach Bottom nuclear power plants will benefit from the work, which would see two boiling water reactors at each receive steam turbine retrofits.

Due to advances in materials, computer modelling and machining, steam turbine technology has advanced steadily since the reactors were built in the late 1960s and 1970s and it is now possible to manufacture new turbine blades and rotors which can make better use of the steam produced by the power reactor. Because the new turbines can be made to fit inside existing casings and fittings, retrofits like this can be carried out during normal refuelling outages, making the process more economic.

Paris-based Alstom will carry out the work using its manufacturing bases at Belfort in France, Morelia in Mexico as well as at a new plant Chattanooga, USA, where it plans to invest over $200 million.

Work has already started at Belfort to manufacture three new low-pressure turbines for Quad Cities. Alstom spokesmen told World Nuclear News there was no officially announced schedule as yet, but the rest of the work would be carried out over the next three to five years and would involve three low-pressure turbine sections for each unit.

Each retrofit should increase the output of the generating unit by about 40 MWe, Alstom said, as well as increase reliability. The retrofit technique is an economic way to increase nuclear capacity, with this project working out at a cost of $1750 per installed kW of new capacity. Current studies on building new nuclear plants in the USA - including premiums for first-of-a-kind risks - suggest a price of around $4000 per kW.

Following its successful applications to the Nuclear Regulatory Commission for license extensions, Exelon plans to operate the Dresden units until 2029 and 2031; the Quad Cities units until 2032; and the Peach Bottom units until 2033 and 2034.